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How to place FreeRTOS in secure memory and the user tasks in non-secure memory?

Yang Zhang

I am porting FreeRTOS with TrustZone on LPC5500, I put FreeRTOS in secure memory, and created several user tasks in non-secure memory, as shown below:

But so far, I have not successfully switched from a secure task to a non-secure task.

How to switch from a secure task to a non-secure task?

Parents
  • 0 Arm Employee Badge in reply to Yang Zhang

    Sorry for delay. I must have missed the notification email (too many emails).

    A task (assume Non-secure unprivileged) can update SP (R13), and if the current selected SP is PSP, then it is updating PSP_NS.

    But normally in an RTOS environment, the initial value of PSP_NS is initialized by the OS (not by the task itself) before the Non-secure task starts.

    regards,

    Joseph

Reply
  • 0 Arm Employee Badge in reply to Yang Zhang

    Sorry for delay. I must have missed the notification email (too many emails).

    A task (assume Non-secure unprivileged) can update SP (R13), and if the current selected SP is PSP, then it is updating PSP_NS.

    But normally in an RTOS environment, the initial value of PSP_NS is initialized by the OS (not by the task itself) before the Non-secure task starts.

    regards,

    Joseph

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